Various different arrangements, for example as shown in U.S. Pat. Nos. 3,265,344; 3,432,134; 3,672,624 and in the applicant's prior U.S. Pat. No. 4,121,801, have been devised for mounting shelf brackets formed of wood composition board or wood so as to extend in cantilever fashion from an upright support. In general, the prior art devices assembled a metal mounting bracket on the shelf bracket and then mounted the metal mounting bracket on the upright support surface. Some of the prior devices, such as shown in U.S. Pat. Nos. 3,265,344 and 3,432,134 utilize screws to assemble the metal mounting bracket on the shelf bracket. In others, such as shown in U.S. Pat. No. 3,672,624, and in one embodiment of my prior U.S. Pat. No. 4,121,801, the metal mounting bracket can be assembled on the shelf bracket member without requiring the use of screws. However, forming of the shelf bracket to receive the metal mounting bracket in such prior devices was such as to require either several sequential woodworking operations on different machines or a releatively complex special machine that could perform several different woodworking operations on the shelf bracket at the same time.